The banks reached an agreement in principle with a group of investors that included the Los Angeles County Employees Retirement Association, Daniel Brockett, a lawyer for the investors, told a judge in Manhattan Federal Court on Friday. The sides need seven to 10 more days to iron out some details, Brockett said.

The investors, including a series of Danish pension funds, in 2013 sued the parent companies or units of about a dozen global banks. These banks, as well as data provider Markit Group Ltd., monopolized trading in the instruments and conspired to control the market for information about them, in violation of U.S. antitrust laws, the investors alleged.

Billions in Profits

The banks “made billions of dollars in supracompetitive profits” by taking advantage of “price opacity in the CDS market,” the investors said.

The banks will pay differing amount toward the settlement, according to two people familiar with the deal. The size of each bank’s payment is based on its share of CDS trading, one of the people said.

Ed Canaday, a Markit spokesman, declined to comment on the deal. Goldman Sachs and JPMorgan also declined to comment. Citigroup and HSBC didn’t immediately reply to requests for comment.

The credit default swaps market was worth $16 trillion as of the end of 2014, according to the Bank for International Settlements. The instruments are used as a hedge against the possibility of a borrower default. Although the contracts trade frequently and fluctuate like stocks or bonds, the market is opaque.

Banks’ Denial

In court papers, the banks said there was no antitrust conspiracy. They argued that members of the group supported proposals to increase competition in the CDS market and that there’s little actual demand for exchange trading of the contracts. In September, they were successful in persuading U.S. District Judge Denise Cote to throw out a claim they colluded to monopolize CDS trading.

Some of the alleged behavior occurred prior to Dodd Frank act of 2010, which regulated the CDS market for the first time, including measures to make the market more transparent and less risky.

The CDS were traded in way that “kept the relevant price information in the hands of the dealer defendants, who ensured they were on one side of, and thus profited from, virtually every CDS transaction,” according to the complaint. As a result, the Wall Street firms and the trade association “successfully maintained an inefficient and opaque market structure that yielded for them exorbitant profits at the direct expense” of the investors suing the banks.

Exclusive Access

The banks had exclusive access to price data, the investors said, forcing them to rely on limited information. The plaintiffs complained that in a typical deal they had no idea how much a broker was profiting from the transaction.

The banks were also accused in the lawsuit of conspiring to sabotage a credit default swap exchange planned by hedge fund Citadel Group LLC and the CME Group Inc., a derivatives market operator. They agreed to boycott the new exchange as long as Citadel was involved, according to the lawsuit, as they considered the hedge fund a “threat.” As a result, potential buyers and sellers had no efficient way to find other potential participants for swaps, unless they were dealers.

Citadel isn’t a plaintiff in the case.

Other banks named as defendants in the case are Bank of America Corp., Barclays Plc, Deutsche Bank AG, BNP Paribas SA, Royal Bank of Scotland Group Plc, Credit Suisse Group AG, Morgan Stanley and UBS AG.

Bank of America, Morgan Stanley, Credit Suisse, Deutsche Bank and Barclays declined to comment on the deal. RBS had no immediate comment. UBS and BNP Paribas didn’t immediately reply to requests for comment.

International Swaps and Derivatives Association, a trade group representing participants in the over-the-counter derivatives market, was also sued. ISDA didn’t immediately respond to requests for comment.

The U.S. Department of Justice’s antitrust division probed the conduct. The agency effectively dropped its investigation in October 2013.

A probe by the European Union’s antitrust arm into whether the banks conspired to shut exchanges out of the credit-default swaps market is still open, according to a person familiar with the matter.